Torsional vibration damper



Jan. 3l, 1933. s R. THOMAS 1,895,825

ToRsIoNAL VIBRATION DAMPER Filed April 29:` 1930 2 sneetsl-sheet 1 Tis.4.

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Jan. 31, 1933.

' s. R. THOMAS 1,895,825

TORSIONAL VIBRATION DAMPER Filed April 29, 1950 l 2 Sheets-Sheet 2 N Q Nd o L 32% s d H* m \N T W M ma, W.

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Pat'ented YJan. 31',

UNITED 1 STATES STANLEY R. 'rHoMAsQoF CLEVELAND, OHIO,ASSIGNOR-'rornnntnss MOTOR'Y CAR CORPORATION, Orr CLEVELAND.' OHIO, ACORPORATION OF VIRGINIA y "TORSIONAL VIBRATION DAMPER Animation meaApril 29,

This invent-ionv relates to improvementsin "vibration dampers forinternal combustion Aeng1nes5 morelspecifica'lly means for dampvingtorsional' vibrations inan engine shaft.

The desirability of a device ofthis character is well recognized' in the`art, particularly in connection with relatively long'orank shafts,

V'where the torsional vibrations are most apparent. p

`Vibration dampers as. heretofore construct'ed have embodied what is ineffect a ""single liy-wheel, loosely mountedi upon that wheel; tends tokeep it rotating at a constant i rate. The power impulses transmitted totheV shaft from the various Apistons produce local -accelerationof speedin the crank shaft, the

metal o-ffthe sliaft being Vresilient enough to i permit this,` and itis these -local accelerations and" succeeding retardatinons that producewhat we call torsional vibration;` The frictional connection lbetweenthe constantly rotating Aflyiwheel and the' vibrating crank' shaft dampoutv these vibrations` more or less completely. Now, I have discoveredthat the Y single unit dampers heretofore in use' are not effective todamp out these vibrations fthr'oughout thev entire range of speeds ofithe modern ant'omobileengine. The mass of the Y auxiliary fly-wheelandthe effectivenessV of` :the friction clutch by means of whichthisHy-wheel is connected with the crank shaft maybe so selected andadjusted that' the vibrations in question Vwill be damped out Y througha given range of speeds, say for in- "stance atall speeds above thirtymiles per hour. In that event the construction and adjustnient'aresuchthat the fly-wheel is actually lo'ckedto the crank shaftA until" suchspeed is attained. On the other hand, if the construction and adjustmentare suoli that the Y flywheel becomesefectiveat lower speeds, say ten ortwenty miles per hour', the friction `connection with the crank shaftisnecessarily so weak that at high speeds there is very littledampingeifect. Y

vvide a pluralfu-nit vibration. damper,thejdif` K ferent uni-ts of whichshall-begin their damp- Y i930. seriar No'. 448,406. l v Accordingly itis an object ofmyinvention vibrations, which shall vbe effectivethroughontth'e speed Vrange of a vehicleengne.

Another `ob]eot of the invention is'to'lproing action successivelyas thespeed of'y rotation' off-the crank shaft reaches?certain.`predetermined-values.' Y i Still another object isthe; provision of avibration damperk of this character in. which the fly-wheelunitslshall-differ inv mass, the coellicients Of friction betweenl the.variousl units and the crankshaft rem-ainingsubstan-f tially equal. Y f

Other objects and features ofnovelty-Will appear as Il proceedV with a.vdescription of those embodiments of the invention which, for thepurposes :Off the present application, I have illustrated in theaccompanying drawingSynwhich 1 I `to provide means fordampingOut'fftorsional y y Figure 1 is a central longitudinal sectionalFig; 3 isa fragmental cross lsectional view i taken substantiallyk ontheline-of Figli2. Fig. 4 isv afragmental cross sectional'zview',Vsimilar toCFi-g.V l', of al modified form ofthe invention.A

Fig. 5= isafront elevational. ,View of aturther modificationyandi i Fig.'6. isV a'central longitudinalk sectionall view taken substantiallyonfthel line 6-61of Flg.5. f

In' the drawings,` I' have .shown at 10 an inner member or hub', adaptedto be slid' onto the forward end of an engine crank shaft,- and providedVwith a keywayflliv by means of which Vit may be locked against'relativerotation. In its forward endl this hub member is provided with acounterbore l2for theV reception of a nut to be threaded .upon the*V soAforward end Vof*` the crankshaft. By "this means they hubfV is heldagainst movement longitudinally ofthel shaft.

Integral' with the hub i011 ferm a-v-puney-'` 13-5, by means' of vwhichdriving/effort maybe fan.

communicated through a V-belt to the engine The Aforward side of thispulley is di formedv vflat and constitutes an i abutment against lwhichrests one face of a friction ring 14 made preferably of fiber'. Thisring the annularportion 15. Y, y Y

.. The twoannular fly-'wheels 16 and17 dii'er considerably in weight, aswill beapparent /6 is ofthe samegeneralcharacter as that yshown inFigs.` 1,y 2 and 3, ando-in so far as -certain parts are commento.thetwo con'-v structions I have employed the same reference fromtheillustration Figs'l fand 3. They are independently .mountedl soY as tobecapableef-rotatQIl relatively toseach other., and

V .in'rorder tofacilitatefsuch'relative rotation I preferably employbetween themv an antifrictionfthrust bearing..y Inthe present in- Ystancethis takes the form-ofanti-friction rollers .18 mounted VinanVVVannular, -cage V19v .supported byv the fly-wheel 16.

' Vrings20 and 21, mounted in the fly-wheels 16 and 17 respectively,form bearing surfaces n against which .theirollers18 work. A secondfriction-'ring 22`is'mounted on the hub infront ofthe inner portion ofrfly-wheel 17 Q Y .In the annular-portion 15 of the hub I Ymount aseries o-studs 23. -A flatl metal ring.,

Y. V24 is perforated at corresponding points in orderto receive'thekstuds.v At positions intermediatethe-studs 23 the-'annular portien 15 is.provided ,with a 'further serieso'f smooth holes 25, and the ring 24.has registering holes providedtherein.l Whenithe-parts are assembleddowels 26 are fitted through the ring Y 24. into the holes :25 and thenkweldedfto the y ring 24, as indicatedatz27. Y By this means thering`-24- isproperly positioned andcenr. tered,.and1as the pins 26 donot extend to the bottom .of the holes 25, the ring can 1nove'longitudinallytofthe Acrank shaft upon` the studs 23.. Itj-isurgedinwardly or rearwardly by coil springs-,28 `and ,29 surroundingy the Y'studs 23 `and l working Aagainst .th'e washers vtension of thefspringsmayb beregulated.V

and nuts 30 and31, by means lof, whichthe When the proper adjustmentsare completed,

a wiretie32 is threaded throughllloles in the l studs28 andlcastellatedslots inthe nut 1,

to lock the latter in place.

two fiy-wheelsand the hub 10.Tothisend, the'cage 38..for the rollers 39:is mounted in the flyewheel 37, but projects into a groove, Y in thefly-wheel 36'to the sameidepth, -inporder i that the dimensions ofthetwo `vfly-wheels may remainjsubstantially identical.l vI-Io-w- Flatsteel ,1

ever, sufficient, clearance isleft between 1the cage 38 andthe walls ofAthegroovevin iiywlreel 36 lto prevent any contact between: them.Bearing rings 40 and 41, similar toV the rings 20 and v21 of the firstdescribed form, are also'pused. Y i

' Between the fly-wheel 36 and the pulley 13 I employv a fiber ring 42similar to the ring 14, but no such ring is used in front of theflywheel A .metal `.ring 44 similar tothe ring 24 of the `firstde's'cribed form, mounted upon studsl 23 and pressed inwardly by springs28 and 29, is also employed.

numeralsfin order that vone description may serve vfor* both.,

The modification illustrated inV Figs. 5 iid .A In the annular portion15 ofthe hubof-thisl 1` modification I kprovide threaded sockets for thereception of studs 45V. IAtfpositions interi mediate the studs 45,onthesamefradius preferably, I providesmoothholes in which', I,mountdowel pins 46. Thestuds v45andY kpins 46` are for the same purposeasthervcor-.V`

responding parts in the first described form of the invention, but theyare somewhat'dif- :ferent 'in construction. y f i vUpon the studs landpins there is supported a llat metal ring 47 ,which is capable of` Tmoving upon thestu'ds a short distance axially of the device.` The pins46 Lare each pro-` vided with anannular groove inwhifchrfisf mountedasplit ring148. These'splitfrings form abutmentsfagainst whichthe-rearface ofthe ring 47 bears. yThisfrin'g 47 is. welded tof eachofthe pins 46 at thejuncture of the front surface of the ring withthepins', as in dicajted at l4,9 in ig. 6. Hence the pins46 are securedagainst movement relative to the `.ring 47, and when the ring movesthepins vslide 'with it in their sockets. ,Y

A second annular plate 50 with a forwardly] loffset peripheral outerportion'51'jisalsoy :mounted upon thestuds 50^and bearsagains't nuts52,'I in the studs. ,Coiledcompression .springs 53' are mountedl atregular'intervals between. ring 47l and they peripheral portion' 51 ofannular plate 50. Suitable meansfare employed to prevent thesespring'sfrom get-y ting out of place. In the present instance I have shown forthis purpose bosses 54, which Vare pressed out of the peripheral portion51 lof the plate 50, andc'ircular pockets '55', ma-

chined into the forwardsurfa'ce Vof ring 47. VSuitably positionedholes56jin the plate 50 serve to clear. the pins 46 and permitmovementof the plate yrelative thereto. Itwill be seen that by removing the coilsprings .from

the studs and locating them on a circle of greater radius .than thestuds, as is done in this modification, the over-,all length ofthedevice may be decreased. Y f -f-y los Referring first to the operationof the preferred form of the invention, when the device is assembledupon the crank shaft of an engine, the nuts 3l are turned down toa'predetermined extent so1 as Ito enable tain pressure. The fly-wheelisgthereby gripped between the friction ring 22 and the rollers 18 witha certain degree of friction, and the fly-wheel 16 lisgripped betweenthe rollers 18 and the frictionring 14 with the same degreerof friction.When the engine is run at speeds below a certain minimum, say thirtymiles per hour, this frictional connection is sufficient to effectivelylockthe lighter flywheel 16 to the hub 10 and thus to the crank shaft,so that this fly-wheel partakes of all the vibrations of the crankshaft. The fly-wheel 17, however, is of such mass that after it has comeup tofspee'd, its inertia is suflicient to overcome fitsfrictionalconnection with the crank shaft. lIt therefore tends to rotateat a continuous even rate during any substantially constant speed of thecrank shaft. The even rotation of this fly-wheel inV turn exerts aneffect upon `the unevenly rotating shaft through the friction connectionbe-k tween them, tending to smooth out orr damp out the vibrations, thatis to say'the variations from regular rotation. v j l 'When thepredetermined speed of thirty miles per hour is reached the inertia ofthe lighter iiy-wheel 16 also becomes sufficient to overcome itsfrictional connection with the crank shaft; From that time on, that isthrough the higher speed ranges, both fly- Wheels tend to keep uptheirregular even rotation and both friction rings 14 and 22 tend to make thecrank shaft accommodate itself to such regular rotation. `Hence thedamping efect is approximately doubled above this critical speed. Thecontrol is of course automatic, and by variations in the weight of therespectivevfly-wheels, by selection of different materials Yfor thefriction rings 14 and 22, and by adjustment of the springs 28 and 29,the critical speed above mentioned may be changed to suit conditions.Thile but two fly-wheels `are`here illustrated and described, it willbe, obvious that a greater number might be employed without departingfrom the spirit of the invention. The operation ofthe form shown vsuflicient, to overcome y the `frictional connec-*i the springs 28 and29 to exert a cerbetween the rollers 39 f and ring 44,. the vcoitsdamping action becomes eective throughoutthe' 4lowerspeedrange. TheHy-wheel 536 is gripped `between fthe rollers `89 and. the friction ring42, and because of the fact that@ thecoefficient of ffrictionbetweenthis ring and the iiywheel ,is relatively high, this iiy wheel vis ineffect locked to the shaft until the critical speed` is reached, whenthedampl ing effectof this fly-wheel is added tothato of the ily-wheel37. Y

lVhile in the foregoing descriptionand in the accompanying drawing Ihave disclosed j certain embodiments` of the'invention more or less indetail, I desire it to be understoodf that such detail disclosure hasbeen resorted `to primarily for the purpose of fully illus- 'i tratingthe invention, and that` it is not to." beconstrued as amounting `to alimitationV Y upon the scope thereof. m90

Having thus described my invention, I claim:

1. In a vibration damper for engine shafts, a hub adapted to be securedto the engine shaft, a fixed abutment at one endof said hub??95 a pairof ily-wheels supported upon and independently rotatable with respect tosaid hub, saidriiy-wheels being of unequal mass, a friction ringinterposed between said abutment and the adjacent fly-wheel, a ringroi/310-0 tatable with and slidable axially upon the opposite end ofsaid hub, and resilient means for causing said last named ring to exertpressure against the adjacent fly-wheel whereby said pressure istransmitted tothf second fly-wheel and through said friction ring tosaid abutment. A -Y 2. In a vibration damper for engine shafts, a hubadapted to be secured'to the engine shaft, a fixed abutment at one end.of said2110 the remote sides of said fly-wheels, a metalfus.

ring rotatable with and slidable axially upon said hub at the endthereof which is remote from said abutment, and resilient means forexerting pressure upon said metal ring in the direction of saidabutment, whereby said fri tion rings are pressed against saidfly-wheels tending to lock the same to said hub. p j

3. In a friction damper for engine shafty ,f' a hub adapted to besecured to the engini shaft, a fixed abutment atV one end of said"* hub,a pair of ily-wheels supported upon and independently rotatable withrespect to said hub, `said fly-wheels being of unequal mass,"anti-friction means interposed between said,

`fly-wheels, friction rings supported upon saidf 139 a, metal'rngrotatable with and slidable axially uponsad hubatthe end thereof which.is remote from 'Said abutment, and resilientA lmeans for'exertngpressure-upon said metal rngtin the direction of said abutment, Wherebysaid friction rings are pressed aganstgsaid Lily-Wheels to lock the sameto said hub.

l l In. testimony $10;

whe'eofl hereunto affix my r; sigggnature. x v, 'e .v Y

' f Y vSTANLEYRVTHOMASL

